Rocky's suit is done and now all he wants to do is to care for Grace's needs even if for a day. (For science, obviously...) He yearns to finally cuddle, feed him meals, bathe him, tuck him in... And maybe he is too heavy to lay on Grace's chest but, -
You know what I really like about Grace? The way he is definitely not a hero and he is so scared about 90% of the time, but his curiosity and sense of wonder are sometimes stronger than his fear. That what makes him occasionally brave even before he meets Rocky.